Process of obtaining the cyanogen compound of an alkali metal



UNITED STATES JOHN COLLINS CLANCY, F FREEPORT, NEW YORK ASSIGNOR TO THE NITROGEN COR PORA'I'ION, OF PROVIDENCE, RHODE ISLAND, A CORPORATION OF RHODE ISLAND.

PROCESS OF OBTAINING THE CYANOGEN COMPOUND OF AN ALKALI METAL.

No Drawing. Application filed July 13,

To all whom it may concern it known that I, J OHN CoLLINs GLnNOY, a citizen of the United States, resid ng I at Free ort, in the county of Nassau and btate of i ew York, have invented certain new and useful Improvements in Processes of Obtaining the Cyanogen Compound of an Alkali Metal, of which the following andcyanami s ma deval, which, as is Well known, became pubme of commercial success.

The cost of separationof the products of this known process has, however, proven to be the source of considerable objection thereto.

Briefly, this known process depends upon the fact that bariumpossesses the property of readily fixing nitrogen. I have discovered, too, that'strontium, also, possesses this property; to aneven greater degree. Barium carbonate, however, is comparatively inexpensive and as it does not markedly tend to attack the apparatus in which the operation is usually conducted, and as it is also comparatively readily fusible,this substance is to he usually preferred. I

The process is operated in difierent known ways, of which, for-brevity, I shall cite but one.

First a mixture is made consisting of carbonate of barium with twenty to thirty parts of tar, resin, pitch, ,wood charcoal or coke, which mixture is heated in asuitable furnace to a high temperature under the action of a current of air. Under these conditions the baryta absorbs nitrogen with lie about 1862 and has met-with somemeasreat ease, with formation of barium cyanid.

his is in turn converted into alkali cyanid by double decomposition, in aqueous solution, with reproduction of barium carbon- 7 ate; thus Specification of Letters were.

next to impossible.

Patented Sept. *Lihfiii.

1917. Serial No. 180,331.

,' to be evaporated to dryness; but in' practice,

this last is a very tedious and costly proceedmg, and even then a separation of the -alkali cyanid .in substantially pure condit on 1s The problem or cheaply and eiiiciently' separating pure potassium or sodium cyanid from the reformed barium. carbonate, to

gether with the Na-,CO in solution, is one which seems, therefore, heretofore not to I have been solved with complete satisfaction.

I have discovered several things of importance in connection with this process. First, that temperatures as high as those commonly used-'z'. e. 1400 (J. or thereabout ,are by no means necessary; but that on the contrary thebaryta, in the presenee of 'carbon, or, less advantageously, even in the absence of carbon -if subjected to a current of substantially vpure nitrogen, or even of reasonably pure producer-gas, can be caused to fix nitrogen at a temperature as low as 800? to900 (1., or in other words at a low red heat, and this especiallyif a small tially in the charge. v v

This initially provided 'cyanid is by no means essential, but it seems to favor the starting of the process at the low tempera amount of barium cyanid' be present initure noted, although in so doin it does not,

I believe properly speaking, "behave as a catalyzer; since it is" itself of the' same substance, as the product to be'first produced. The reaction which takes place in the furnace may therefore be set forth as follows:

B co FN, tie-n8 010 4-300.

be fused at a 10W red heat with, for example,

sodium carbonate in the presence of carbon, the double decomposition is efiected thus ZNaON Baflfifl -t Q. If barium oxid lie-present some oxid of the alkali metal might form were it notfor the presence of the added carbon; but insofar as the separation now to be described is concerned, this: is immaterial for the roe: son hereinafter glven,

The fused mixture of alkali cyanid and carbonate is now cooled and the mass broken up into, preferably, small particles, which are then treated with liquid ammonia in a closed air and gas tight-receptacle.

Ammonia, as is known, possesses the property of dissolving alkali cyani-ds but the solvent action of this substance upon many salts has not to the best of my knowledge been very fully investigated.

1 have discovered that the barium carbonate, and, indeed, all of the reaction prod nets in question are practically? wholly insoluble in this liquid, with the single exception of the alkali cyanid to be separated therefrom;

Thus, therefore, not

only is the carbonate I of barium, or its equivalent herein, insoluess may *When the solution: is

ble in liquid ammonia, but further any traces of barium oxid, for example, or of the alkali carbonate, or alkaline earth metal cyanid, which may be present, will be left unacted upon.

drained or drawn off, it contains substantially nothing but pure alkali cyan'id; which is readily recovered! therefrom by subjecting the liquid to a gentle heat. The entire recovery operation is preferably so'conducted as to exclude air, and the ammonia is collected and condensed in suitable refrigerating apparatus reparatory to its re-use. I

The alkali cyanid is obtained, in prac-. tice, as a very nearly chemically pure white crystalline product.

In general, while the above described procbe defined as a dry process, in contradistinction to others which involve the use of Water, either to afford a desired bonate of an alkaline earth ate, reacting upon with the carbonate'of an.

reaction or for leaching purposes; it is nevertheless possible, although not so desirable, to dissolve the barium cyanid containing reaction mass in a small quantity of water and to then add the calculated amount of sodium carbonateto form, on heating, sodium cyanid and barium carbonate; the pasty mass, so obtained, being evaporated to dryness. After cooling, the leaching with liquid ammonia can be effected subalkali cyanid and permit the barium carbonate to be returned to the furnace. i

alkali metal cyanogen compounds are soluble in liquid ammonia and since cyanamids may be formed in lieu 0 or from cyanids, in various ways, I desire it to be understood that'I do not limit my the production of an invention merely to alkali cyanid, p61; 86.

Having thus described my invention, I claim is:

The process of producing which comprises effecting ing reaction of free nitrogen what a cyanid ormupon the carmetal by initially admixing acyanid with the alkaline earth metal cyanid produced, alkali metal to reform said carbonate of'an alkaline earth the former.

In testimony signature, in the presence of two witnesses.

JOHN COLLINS CLANOY.

' \Vitnesses FRANCIS G. SMITH, Jorrn C. BAXTER.

said carbonmetal and to form the prod-- not sought, and extracting the latter from stantially as aforesaid, to dissolve out the;

an alkali c anid whereof I have affixed my 

